In computer engineering, different kinds of pointers and positioning means are used as input units, such as a joystick, a control ball, a mouse etc, which in manual operation generate electric control signals for multidimensional controlling, position control in CAD work or in computer and TV games often requires controllability within several degrees of freedom or dimensions. A user should be able to perform with his hand a number of different controlling movements in a logic or intuitive manner. In some modern applications, especially computer games, controllability is required in up to six dimensions, for example a linear movement in three directions and a rotating movement in three directions.
In the present application, the term "pointer" is to be interpreted in a wide sense and comprise all types of input units with one or more movable operating means for generating position control signals for multidimensional controlling of on object, by operating said operating means in different directions of operation.
SE-5,022,186 discloses an input unit in the form of a pointer for three-dimensional position control of e.g. a cursor on a display. An object, which especially can be the user's finger, is illuminated by two point sources of light. As a result, the object casts two shadows on a detector surface, which is made up of a plurality of separate detector elements for determining the absolute positions of the shadows. The position of the object in three dimensions is calculated on the basis of the absolute and relative positions of the two shadows.
This prior-art pointer has a relatively high total cost of components and may be difficult to manufacture with small dimensions, which prevents the pointer from being used as a partial component in more complex controlling devices. The reliability is limited. The size of the operating area is limited by the components.
For conversion of movements of a pointer into control signals, it is also known to use components of the PSD type (Position-Sensing Detector) or CCD type (Charge Coupled Device). However, these components are complicated and consequently expensive.
The International Patent Application under Publication No. WO 97/05567, which was filed before the priority date of the present application but was published after the priority date of the present application, discloses a pointer in the form of a control lever for controlling in several dimensions. In one embodiment, the operating handle supports a light source at its lower end. A stationary detector has four detector surfaces in the form of photodiodes, each forming a quadrant. Radiation from the movable source of light passes through an opening in a stationary screen and falls as a light spot on the detector surfaces. When the control lover is moved, the amount of light on the various detector surfaces varies. The current angular position of the operating handle in calculated on the basis of a comparison of light intensity on the various detector surfaces.